Scale Definition and 743 Threads

So, we have to build this scale in mechatronics class that weighs things as small as a dime to as large as however we want, but it has to weigh a dime. I came up with this idea that will be constructed with legos: A pully (20 cm radius) will be fixed on a shaft with a cup kindda thing hanging...

I'm wondering what happens if the scale factor of cosmological expansion increases without limit? Will you always calculate the same quantum foam and virtual particle production rates no matter what the scale is of the universe's expansion? If particles are extended objects, then of course...

Just a quickie I'm taking a slice of a galaxy picture and plotting luminosity vs kpc. I'm fitting a luminosity profile (de vacouleurs) and keeping disk scale length as a free parameter. However, textual values for this (referred to as h from now on) range between 3-4 kpc for most galaxies. h...

Space time question. Before I ask my question I suppose I should ask a preliminary question that will tell me if my actual question has an answer. Does space time only exist in space? If so, is Earth's surface considered space, thereby abiding by space times rules? Also, theoretically if we...

A 20.8 kg mass attached to a spring scale rests on a smooth, horizontal surface. The spring scale, attached to the front end of a boxcar, reads T = 38.7 N when the car is in motion. If the spring scale reads zero when the car is at rest, determine the acceleration of the car, when it is in...

Here's a question. I don't have any problem getting the answer, or identifying the forces, but I'm having trouble explaining why the scale reads what it does. A woman of mass 65 kg stands inside an elevator on a bathroom scale calibrated to read in Newtons. Calculate the scale reading in...

What does it mean for a matrix or a vector to be "defined up to scale"? I don't remember ever seeing this expression in my very limited exposure to linear algebra. To put it in context, I'm finding it in a text on computer vision in the section on geometric camera models. They're talking...

Most commercial nuclear fission reactors are large, on the 1000MW order of magnitude. Some of the early experimental reactors were small, and the reactors in nuclear submarines are relatively small. I understand that the Navy even has one very small (crew of 7 people, 400 tons v...

Clauset and Young, in their new paper http://www.arxiv.org/PS_cache/physics/pdf/0502/0502014.pdf , apply standard modern statistics to a database of terrorist strikes ordered by the number of people killed or injured. They find that extreme cases, such as 9/11, are not outliers, but find their...

1. A student stands on a bathroom scale in an elevator at rest on the 64th floor of a building. The scale reads 836 N. As the elevator moves up, the scale reading increases to 936 N, then decreases back to 836 N. Find the acceleration of the elevator. 2. The instruments attached to a weather...

if you stand on a bathroom scale, the spring inside the scale compresses .50 mm, and it tells you your weight is 700 N. Now if you jump on the scale from a height of 1.4 m, what does the scale read at this peak. i found an equation to use, i just can't figure out what I'm solving for. I'm...

The question is I have to convert my scores to GPA system. But first I have to know how you calculate the GPA number over a scale of 4. I'm figuring it out as: GPA=\frac{4}{10}\frac{\sum n_i Q_i}{\sum n_i} where n=credits of the course (here 1 credit=10 hours attended) Q=score. Here...

The scale factor in the R-W metric is there to account for the expansion of the universe. My question is whether this scale factor is put in by hand just to account for observations? Or can it be derived from more basic assumptions? Thanks.

I'm new to this stuff, so the question may be really simple, but I just can't work it right... Alright, so the question I'm trying to figure is this: The student's normal weight is 500 N. He stands on a scale in an elevator and records the scale reading as a function of time. So for the...

If you stand on a bathroom scale, the spring inside the scale compresses 0.50 mm, and it tells you your weight is 805 N. Now if you jump on the scale from a height of 2.0 m, what does the scale read at its peak? I used F=kx, and solved for k...but I don't know what to do after that...do I set...

Hi I'm in grade 11 physics and my teacher assigned a question where he asked "What does a bathroom scale measure? Explain you're reasoning" Ok for this I would say it measures normal force, according to Newton's 3rd law you apply a force on the scale it exerts a force back on you and that is...

I am designing a lab to prove that F=ma. However i am only using a spring scale, 1 kg mass, string. I have come up with a procedure where you would attach the mass to the scale and accelerate the unit upward, recording the time it takes the unit to accelerate from 0-1m and the force shown in the...

Two physics students are having a debate about the best way to define a force scale using rubber bands. Each one is trying to convince you to do it their way. They have the following apparatus to use in tests: A bunch of identical small rubber bands 10N spring scale meter stick Joe...

"Planck scale Lorentz-symmetry test theories" Amelino-Camelia new paper by Giovanni A-C http://arxiv.org/abs/astro-ph/0410076

According to the big-bang model, it is assumed that when the universe was young enough (lets say z > 1100), the density fluctuations did evolve in the linear regime. Due to this fact, one can make use of simple linearized formulas such as the continuity, Poisson and Euler equations to model the...

large scale electromagnetic hover sculpture... HELP! [really quite urgent...] Hi all! i'm a design student, trying to find out about the feasibility of a project I'm working on... http://i.1asphost.com/s2mega/magnet.jpg the concept goes like this: a "bowl" structure, lined with...

large scale electromagnetic hover sculpture... HELP! [really quite urgent...] http://i.1asphost.com/s2mega/magnet.jpg Hiya all~~ I'm a design student, and I'm in search of anyone who may be able to assist in determining the feasibility of the above design... URGENTLY... i have...

In post #55 of the A&C reference sticky there's a link to the February WS-2004 symposium on Quantum Gravity Phenomenology http://ws2004.ift.uni.wroc.pl/html.html this is about the predictions coming out of Quantum Gravity and ongoing or planned opportunities to test. what I have to...

Third scale QG that Smolin and others are working on attempts to incorporate 3 invariant scales (the speed c, the Planck mass kappa, and the length L = Lambda-1/2) and to have 3SR---triply special relativity---as its flat limit. this research direction has been attracting more people lately...

hey all... Im having trouble with a question here that asks when only 2 forces act on an object (1: 8.0 to the right, 2: 12.0 N to the left) draw a scale diagram to determine the magnitude and direction of the resulting NET force. anyone know how to do this? anyone know how to draw a...

Hi all, I was wondering if anyone of you has read the book of Laurent Nottale Fractal Space-Time and Microphysics: Towards a Theory of Scale Relativity why is not his approach adopted ?- as apparently, he extended the principle of relativity to scales and thus proposes a unifying...

Anyone have some ideas about how to build a scale model of a trebuchet?

This paper : Hyperbolic Universes with a Horned Topology and the CMB Anisotropy http://arxiv.org/astro-ph/0403597 ...press release: http://www.newscientist.com/news/news.jsp?id=ns99994879 proposes a universe with the shape of a horn. This is a hyperbolic space with negative...

I need help on this problem: Suppose you stand on a bathroom scale on one of the Earth's poles, and it reads 700.0 N. If you stand on the same scale on the Earth's equator, and your mass is unchanged, what will be the scale reading on the equator? (Remember that the scale tells you the normal...

What is the most commonly used scale of sharpness? Does anyone know a webpage with examples of the comparitive sharpness of various things?

We have a helicopter flying and use the power "P" to keep it in equilibrium. But if the scale was greater n times, what would be the power to keep it there?

Why the Kelvin termo scale has no negative values? I'm just asking if some one knows and is it ok and why.

Thermal physics question... A wire resistance thermometer is constructed with material that has a resistance that varies as temperature as below. R=R0 (1+ alphaT + betaT^2) where constants alpha and beta are 3.8 x 10^-3 k^-1 and -3.0 x 10^-6 k^-2 respectively. Calculate the...

Let's present a scale of frequencies of light. For initial we’ll take frequency of visible light. Here particle / wave duality is shown fifty- fifty. At increase or decrease of frequency this proportion is broken. Frequency increasing. Properties of a particle...

Please help me with the following 4 questions if you can (I want to double check my answers)... 1. A 24.5 kg child sits on a bathroom scale which is placed on the seat of a swing. What does the scale read when the swing is at rest? The child begins to swing back and forth until she reaches a...

For those of you familiar with numerical modelling of various phenomena, you will know about work like the various discretisation schemes, stability/gradient limiters for high order schemes and so on. The most broad sweeping improvement to the field of numerical modelling would ultimately be...

I need help! I am practicing out of my book and this problem is killing me. Given the following equation, choose the best scale for the axes for x = 10, 20, and 30 y = 2x – 3 A) x-axis: from 0 to 80, intervals every 20; y-axis: from 0 to 40, intervals every 10. B)...

By whatever means that you may imagine, is this possible? I say yes.

How many points are there on the Beaufort scale for measuring wind force?

I have found references to a book that is either "to appear" or has already been published by Cambridge University Press. The book is Physics meets Philosophy at the Planck scale edited by C. Callender and N. Huggett this is apparently a collection of essays by philosophers and...

This is just to defer a discussion that began in the Religion forum concerning https://www.physicsforums.com/showthread.php?s=&threadid=429&perpage=15&pagenumber=3". It seems there are two approaches: the seven note diatonic scale, i.e., do, re, mi, fa, so, la, ti, do, developed by Guido...

On a scale from 0 to 10 what does A equal to ? And B, C,... ? (I mean grades...at school)

This question has been troubling me... : A physics teacher decides to use bathroom scales (calibrated in Newtons) in an elevator. The scales provide a measure of the force with which they push up on the teacher. When the lift is stationary the reading on the bathroom scales is 823 N. What...